Government needs to redraw drought plan, expert says

Staff writer, with CNA

Thu, Mar 28, 2013 - Page 5

The government should consider creating rain artificially before the onset of water shortages if it wants to solve the problems caused by lack of rainfall, an atmospheric expert said.

“The government should routinely seed clouds in early winter,” said Chen Jen-ping (陳正平), a professor at National Taiwan University’s Department of Atmospheric Sciences.

Chen, who also advises the Water Resources Agency, made the recommendation after recent rainmaking efforts to relieve an extended dry spell proved fruitless.

A cloud seeding operation near the Shihmen Reservoir (石門水庫) catchment area in Taoyuan County had to be abandoned last week because of a lack of moisture in the atmosphere. Subsequent attempts conducted near the Shihmen Reservoir and Ming-Te Reservoir (明德水庫) in Miaoli County on Sunday were carried out successfully, but generated almost no precipitation due to the poor tracking of rain clouds.

Chen said the technique, which sends plumes of calcium chloride smoke into rain clouds to encite precipitation, must be conducted using a long-term plan and precise calculations to be effective.

The best time for cloud seeding is in the winter, when slow-moving fronts and thicker cloud bands carrying abundant moisture are more likely to produce positive effects, he said. Seeding clouds in winter instead of in spring, when water reserves typically decline, would also give the government more time to devise other solutions if drought conditions persisted, he added.

Chen added that the Central Weather Bureau needed to upgrade its high-resolution satellite image processing technology if it hoped to seed clouds more successfully. Better technology could help track air masses more accurately and identify the best opportunities to generate rain, he said.

The bureau’s current technology enables it to see clouds, but not to determine their movements, characteristics or development, making it impossible to predict which ones are suitable for seeding at which time.